Elle was staying with us about a year ago, and she was walking around topless. My mother was a little upset but I told her, ”PLEASE! This girl’s body is a national treasure!” — Katie Ford, 38, copresident of Ford Modeling Agency and daughter of founder Eileen Ford.

National treasure or not, Elle Macpherson, one of a legion of supermodels who have turned their natural assets into million-dollar industries, is looking a little nervous as she sits on a couch at a ski house at the Sundance Film Festival in Park City, Utah. Dressed in a skintight black catsuit and ski sweater, Macpherson, 30, is worried about tonight’s premiere of her first movie, the erotic Sirens. ”If this were my own environment, I’d know exactly who was going to be there and exactly what was going on,” she says. ”But I feel like a fish out of water. This is all very new and I’m just learning how it works.”

It might be new to her, but the path of models who try to make the move into acting has long been strewn with disaster. Two words: Ali MacGraw. Two more words: Christie Brinkley. Will Macpherson make the leap from mannequin to movie star? Surprisingly, both Sirens and its star are getting some good reviews, and not just for Elle’s 6-foot, 125-pound, often-naked body. This may cheer the swelling ranks of ’90s supermodels who are trying to cross over to acting-a list that includes Vendela, Anna Nicole Smith, Kathy Ireland, Tyra Banks, Kristen McMenamy, Veronica Webb, Angie Everhart, Tasha, Liv Tyler, and Karina Lombard, among others.

But despite Macpherson’s case of Sundance jitters (she made an early exit from an overcrowded Miramax party with her hunky boyfriend — London gallery owner Tim Jefferies, 32 — looking overwhelmed by the all-in-black, intense, bespectacled film folk), she and other supermodels have a lot less to worry about when it comes to switching career gears. Unlike years past, when models had a shelf life of five to six years at best and acting was their only shot at a legitimate fallback, today’s bunch are bigger than most movie stars — and their influence on pop culture far more pervasive.

Interest in the modeling world has never been so — to use the favorite expression of fashion photographers this season — fierce. Aaron Spelling’s new Melrose Place spin-off is called Models, Inc. Robert Altman began shooting his pseudo- documentary Prêt à Porter this month at the Paris fashion shows. Elle Top Model, a new magazine devoted to models, debuts this month.

”If you look at Christy Turlington, Cindy Crawford, Claudia Schiffer, Linda (Evangelista), or Naomi (Campbell), those women are better known than any actresses,” says John Casablancas, 5l, the chairman of Elite. ”They’ve become the Brigitte Bardots and Marilyn Monroes of today.” In fact, the model- industrial complex has transcended its roots; it’s as much a part of the entertainment industry as it is the fashion business.

Which means models are no longer the stepchildren of showbiz. Their sphere of influence has expanded from magazine covers, cosmetic ads, and runway shows to movies, music, television, video, even, for lack of a better description, journalism. In other words, esteemed broadcast journalist Cindy Crawford, host of MTV’s House of Style and the Edward R. Murrow of fashion, is not the only model to have figured out that there’s serious money to be made just by capitalizing on your day job. ”There’s been a real Hollywoodization of models,” says Veronica Webb, 29. ”Everyone used to fantasize about being a movie star, but nowadays it’s easier to legitimize yourself as a supermodel than an actress.”

While still the most prestigious gig models can get, acting — even for today’s most successful model-actress, Andie MacDowell — is now just one more notch in their Prada belts. ”You can’t imagine the money you make now compared to before,” says Eileen Ford, 71. ”You’re really talking about the world’s best salespeople. Models reach millions and millions of women through TV and video and print.”

To that end, runway queen Naomi Campbell is planning a long-awaited album for Epic; Elizabeth Arden’s Vendela was a ”guest reporter” for Entertainment Tonight at the Winter Olympics; eyebrow-free Kristen McMenamy made her Off Broadway debut in One Flew Over the Cuckoo’s Nest; Tasha is playing herself on NBC’s soap Another World; Angie Everhart appeared in Last Action Hero and TV’s The Mommies; MTV VJ Daisy Fuentes has a new talk show on CNBC and a lucrative Revlon contract; former Estee Lauder model Willow Bay is the new coanchor of Good Morning America Sunday; Sports Illustrated favorite Roshumba is the host of Black Entertainment Television’s Shades: The Dark Side of the Runway; and Dana Patrick calls herself ”every 15-year-old boy’s wet dream” as Meatloaf’s love interest in the smash video of ”I Will Do Anything for Love.”